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1 /*
2  * Copyright © 2011,2012  Google, Inc.
3  * Copyright © 2018  Ebrahim Byagowi
4  *
5  *  This is part of HarfBuzz, a text shaping library.
6  *
7  * Permission is hereby granted, without written agreement and without
8  * license or royalty fees, to use, copy, modify, and distribute this
9  * software and its documentation for any purpose, provided that the
10  * above copyright notice and the following two paragraphs appear in
11  * all copies of this software.
12  *
13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17  * DAMAGE.
18  *
19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24  *
25  * Google Author(s): Behdad Esfahbod
26  */
27 
28 #ifndef HB_OT_OS2_TABLE_HH
29 #define HB_OT_OS2_TABLE_HH
30 
31 #include "hb-open-type.hh"
32 #include "hb-ot-os2-unicode-ranges.hh"
33 
34 #include "hb-set.hh"
35 
36 /*
37  * OS/2 and Windows Metrics
38  * https://docs.microsoft.com/en-us/typography/opentype/spec/os2
39  */
40 #define HB_OT_TAG_OS2 HB_TAG('O','S','/','2')
41 
42 
43 namespace OT {
44 
45 struct OS2V1Tail
46 {
sanitizeOT::OS2V1Tail47   bool sanitize (hb_sanitize_context_t *c) const
48   {
49     TRACE_SANITIZE (this);
50     return_trace (c->check_struct (this));
51   }
52 
53   public:
54   HBUINT32	ulCodePageRange1;
55   HBUINT32	ulCodePageRange2;
56   public:
57   DEFINE_SIZE_STATIC (8);
58 };
59 
60 struct OS2V2Tail
61 {
sanitizeOT::OS2V2Tail62   bool sanitize (hb_sanitize_context_t *c) const
63   {
64     TRACE_SANITIZE (this);
65     return_trace (c->check_struct (this));
66   }
67 
68   public:
69   HBINT16	sxHeight;
70   HBINT16	sCapHeight;
71   HBUINT16	usDefaultChar;
72   HBUINT16	usBreakChar;
73   HBUINT16	usMaxContext;
74   public:
75   DEFINE_SIZE_STATIC (10);
76 };
77 
78 struct OS2V5Tail
79 {
sanitizeOT::OS2V5Tail80   bool sanitize (hb_sanitize_context_t *c) const
81   {
82     TRACE_SANITIZE (this);
83     return_trace (c->check_struct (this));
84   }
85 
86   public:
87   HBUINT16	usLowerOpticalPointSize;
88   HBUINT16	usUpperOpticalPointSize;
89   public:
90   DEFINE_SIZE_STATIC (4);
91 };
92 
93 struct OS2
94 {
95   static constexpr hb_tag_t tableTag = HB_OT_TAG_OS2;
96 
has_dataOT::OS297   bool has_data () const { return this != &Null (OS2); }
98 
v1OT::OS299   const OS2V1Tail &v1 () const { return version >= 1 ? v1X : Null (OS2V1Tail); }
v2OT::OS2100   const OS2V2Tail &v2 () const { return version >= 2 ? v2X : Null (OS2V2Tail); }
v5OT::OS2101   const OS2V5Tail &v5 () const { return version >= 5 ? v5X : Null (OS2V5Tail); }
102 
103   enum selection_flag_t {
104     ITALIC		= 1u<<0,
105     UNDERSCORE		= 1u<<1,
106     NEGATIVE		= 1u<<2,
107     OUTLINED		= 1u<<3,
108     STRIKEOUT		= 1u<<4,
109     BOLD		= 1u<<5,
110     REGULAR		= 1u<<6,
111     USE_TYPO_METRICS	= 1u<<7,
112     WWS			= 1u<<8,
113     OBLIQUE		= 1u<<9
114   };
115 
is_italicOT::OS2116   bool is_italic () const       { return fsSelection & ITALIC; }
is_obliqueOT::OS2117   bool is_oblique () const      { return fsSelection & OBLIQUE; }
is_typo_metricsOT::OS2118   bool is_typo_metrics () const { return fsSelection & USE_TYPO_METRICS; }
119 
120   enum width_class_t {
121     FWIDTH_ULTRA_CONDENSED	= 1, /* 50% */
122     FWIDTH_EXTRA_CONDENSED	= 2, /* 62.5% */
123     FWIDTH_CONDENSED		= 3, /* 75% */
124     FWIDTH_SEMI_CONDENSED	= 4, /* 87.5% */
125     FWIDTH_NORMAL		= 5, /* 100% */
126     FWIDTH_SEMI_EXPANDED	= 6, /* 112.5% */
127     FWIDTH_EXPANDED		= 7, /* 125% */
128     FWIDTH_EXTRA_EXPANDED	= 8, /* 150% */
129     FWIDTH_ULTRA_EXPANDED	= 9  /* 200% */
130   };
131 
get_widthOT::OS2132   float get_width () const
133   {
134     switch (usWidthClass) {
135     case FWIDTH_ULTRA_CONDENSED:return 50.f;
136     case FWIDTH_EXTRA_CONDENSED:return 62.5f;
137     case FWIDTH_CONDENSED:	return 75.f;
138     case FWIDTH_SEMI_CONDENSED:	return 87.5f;
139     default:
140     case FWIDTH_NORMAL:		return 100.f;
141     case FWIDTH_SEMI_EXPANDED:	return 112.5f;
142     case FWIDTH_EXPANDED:	return 125.f;
143     case FWIDTH_EXTRA_EXPANDED:	return 150.f;
144     case FWIDTH_ULTRA_EXPANDED:	return 200.f;
145     }
146   }
147 
subsetOT::OS2148   bool subset (hb_subset_context_t *c) const
149   {
150     TRACE_SUBSET (this);
151     OS2 *os2_prime = c->serializer->embed (this);
152     if (unlikely (!os2_prime)) return_trace (false);
153 
154     uint16_t min_cp, max_cp;
155     find_min_and_max_codepoint (c->plan->unicodes, &min_cp, &max_cp);
156     os2_prime->usFirstCharIndex = min_cp;
157     os2_prime->usLastCharIndex = max_cp;
158 
159     _update_unicode_ranges (c->plan->unicodes, os2_prime->ulUnicodeRange);
160 
161     return_trace (true);
162   }
163 
_update_unicode_rangesOT::OS2164   void _update_unicode_ranges (const hb_set_t *codepoints,
165 			       HBUINT32 ulUnicodeRange[4]) const
166   {
167     for (unsigned int i = 0; i < 4; i++)
168       ulUnicodeRange[i] = 0;
169 
170     hb_codepoint_t cp = HB_SET_VALUE_INVALID;
171     while (codepoints->next (&cp)) {
172       unsigned int bit = _hb_ot_os2_get_unicode_range_bit (cp);
173       if (bit < 128)
174       {
175 	unsigned int block = bit / 32;
176 	unsigned int bit_in_block = bit % 32;
177 	unsigned int mask = 1 << bit_in_block;
178 	ulUnicodeRange[block] = ulUnicodeRange[block] | mask;
179       }
180       if (cp >= 0x10000 && cp <= 0x110000)
181       {
182 	/* the spec says that bit 57 ("Non Plane 0") implies that there's
183 	   at least one codepoint beyond the BMP; so I also include all
184 	   the non-BMP codepoints here */
185 	ulUnicodeRange[1] = ulUnicodeRange[1] | (1 << 25);
186       }
187     }
188   }
189 
find_min_and_max_codepointOT::OS2190   static void find_min_and_max_codepoint (const hb_set_t *codepoints,
191 						 uint16_t *min_cp, /* OUT */
192 						 uint16_t *max_cp  /* OUT */)
193   {
194     *min_cp = codepoints->get_min ();
195     *max_cp = codepoints->get_max ();
196   }
197 
198   enum font_page_t {
199     HEBREW_FONT_PAGE		= 0xB100, // Hebrew Windows 3.1 font page
200     SIMP_ARABIC_FONT_PAGE	= 0xB200, // Simplified Arabic Windows 3.1 font page
201     TRAD_ARABIC_FONT_PAGE	= 0xB300, // Traditional Arabic Windows 3.1 font page
202     OEM_ARABIC_FONT_PAGE	= 0xB400, // OEM Arabic Windows 3.1 font page
203     SIMP_FARSI_FONT_PAGE	= 0xBA00, // Simplified Farsi Windows 3.1 font page
204     TRAD_FARSI_FONT_PAGE	= 0xBB00, // Traditional Farsi Windows 3.1 font page
205     THAI_FONT_PAGE		= 0xDE00  // Thai Windows 3.1 font page
206   };
207 
208   // https://github.com/Microsoft/Font-Validator/blob/520aaae/OTFontFileVal/val_OS2.cs#L644-L681
get_font_pageOT::OS2209   font_page_t get_font_page () const
210   { return (font_page_t) (version == 0 ? fsSelection & 0xFF00 : 0); }
211 
get_sizeOT::OS2212   unsigned get_size () const
213   {
214     unsigned result = min_size;
215     if (version >= 1) result += v1X.get_size ();
216     if (version >= 2) result += v2X.get_size ();
217     if (version >= 5) result += v5X.get_size ();
218     return result;
219   }
220 
sanitizeOT::OS2221   bool sanitize (hb_sanitize_context_t *c) const
222   {
223     TRACE_SANITIZE (this);
224     if (unlikely (!c->check_struct (this))) return_trace (false);
225     if (unlikely (version >= 1 && !v1X.sanitize (c))) return_trace (false);
226     if (unlikely (version >= 2 && !v2X.sanitize (c))) return_trace (false);
227     if (unlikely (version >= 5 && !v5X.sanitize (c))) return_trace (false);
228     return_trace (true);
229   }
230 
231   public:
232   HBUINT16	version;
233   HBINT16	xAvgCharWidth;
234   HBUINT16	usWeightClass;
235   HBUINT16	usWidthClass;
236   HBUINT16	fsType;
237   HBINT16	ySubscriptXSize;
238   HBINT16	ySubscriptYSize;
239   HBINT16	ySubscriptXOffset;
240   HBINT16	ySubscriptYOffset;
241   HBINT16	ySuperscriptXSize;
242   HBINT16	ySuperscriptYSize;
243   HBINT16	ySuperscriptXOffset;
244   HBINT16	ySuperscriptYOffset;
245   HBINT16	yStrikeoutSize;
246   HBINT16	yStrikeoutPosition;
247   HBINT16	sFamilyClass;
248   HBUINT8	panose[10];
249   HBUINT32	ulUnicodeRange[4];
250   Tag		achVendID;
251   HBUINT16	fsSelection;
252   HBUINT16	usFirstCharIndex;
253   HBUINT16	usLastCharIndex;
254   HBINT16	sTypoAscender;
255   HBINT16	sTypoDescender;
256   HBINT16	sTypoLineGap;
257   HBUINT16	usWinAscent;
258   HBUINT16	usWinDescent;
259   OS2V1Tail	v1X;
260   OS2V2Tail	v2X;
261   OS2V5Tail	v5X;
262   public:
263   DEFINE_SIZE_MIN (78);
264 };
265 
266 } /* namespace OT */
267 
268 
269 #endif /* HB_OT_OS2_TABLE_HH */
270